This invention relates to catalytic reactions. In one of its aspects this invention relates to the introduction of catalyst into a reactor. In another of its aspects this invention relates to a method and apparatus for preparing catalyst mixtures and assuring free flow of the mixture in a controlled amount to the reactor. In another of its aspects this invention relates to the automatic transfer of catalyst mixture to a reactor with delivery of measured quantities without unscheduled stoppage of flow.
In many chemical reactions, particularly in the polymerization of certain hydrocarbon monomers, a catalyst is utilized to promote the chemical reaction. These reactions are sensitive to the quantity of catalysts utilized so that the production rate of the reaction can be controlled by controlling the rate of catalyst feed into the reaction. Any unwarranted stoppage of flow of the catalyst makes control of the reaction unpredictable and can produce serious harm to the quality of the product.
In many catalyst preparation operations a mixture of catalyst ingredients and carrier are apportioned into a catalyst feed tank, often called a mud tank, for thorough mixing before being passed in controlled amounts into the reaction vessel for contact with monomeric reactants. Some catalyst mixtures contain such a proportionally high amount of solid material that it is difficult to prevent settling of the solids in the bottom of the mixing tank. Other catalysts can be coated with polymer often called prepolymer, to provide some control in the particle size distribution of the polymer produced using the catalyst. Such catalyst mixtures often have a tendency to bridge narrow openings in a catalyst mixing vessel. Both of these problems are evident in catalyst mixing systems which use tanks as the mixing vessels, particularly when the flow from the bottom of the tank has been discontinued.
Accordingly, an apparatus has now been devised for improving the agitation near the outlet of a mixing tank which is adequate to provide free flow for catalyst or other mixtures which are viscous or tend to bridge narrow openings. This apparatus has been combined into a system principally for assuring a measured flow of catalyst into a reactor vessel but which is also of use for providing a measured flow of other hard-to-handle mixtures from a mixing vessel.
It is therefore an object of this invention to provide apparatus for assuring agitation of material at the bottom outlet of a tank. It is another object of this invention to provide an agitated catalyst mixing tank. It is another object of this invention to provide a ball check feed valve operable for transferring polymer coated catalyst. It is still another object of this invention to provide method and apparatus for assuring free flow of a measured amount of material, particularly catalyst, from a mixing vessel.
Other aspects, objects and the various advantages of this invention will become apparent upon reading this specification, studying the drawing, and reading the appended claims.